Adding UMA stats for dragdrop events for both touch and mouse.

ui/views/widget/desktop_aura/desktop_drag_drop_client_aurax11.cc

Index: ui/views/widget/desktop_aura/desktop_drag_drop_client_aurax11.cc
diff --git a/ui/views/widget/desktop_aura/desktop_drag_drop_client_aurax11.cc b/ui/views/widget/desktop_aura/desktop_drag_drop_client_aurax11.cc
index 8a56b8de9689f8132adc9f2190b3154f4dced4b0..52200a77880259acabfb6d7f5799af5dd9e23640 100644
--- a/ui/views/widget/desktop_aura/desktop_drag_drop_client_aurax11.cc
+++ b/ui/views/widget/desktop_aura/desktop_drag_drop_client_aurax11.cc
@@ -6,9 +6,13 @@
 
 #include <X11/Xatom.h>
 
+#include <map>
+#include <utility>

[mfomitchev, 2015/01/13 17:01:25]

why are these new imports needed?

[caelyn, 2015/01/13 23:48:58]

See reasoning from the .h file.

+
 #include "base/event_types.h"
 #include "base/lazy_instance.h"
 #include "base/message_loop/message_loop.h"
+#include "base/metrics/histogram_macros.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "ui/aura/client/capture_client.h"
 #include "ui/aura/window.h"
@@ -417,6 +421,7 @@ DesktopDragDropClientAuraX11::DesktopDragDropClientAuraX11(
       source_current_window_(None),
       source_state_(SOURCE_STATE_OTHER),
       drag_operation_(0),
+      current_drag_event_source_(ui::DragDropTypes::DRAG_EVENT_SOURCE_MOUSE),
       negotiated_operation_(ui::DragDropTypes::DRAG_NONE),
       weak_ptr_factory_(this) {
   // Some tests change the DesktopDragDropClientAuraX11 associated with an
@@ -646,6 +651,9 @@ int DesktopDragDropClientAuraX11::StartDragAndDrop(
     const gfx::Point& root_location,
     int operation,
     ui::DragDropTypes::DragEventSource source) {
+  UMA_HISTOGRAM_ENUMERATION("DragDrop.Start", source,
+                            ui::DragDropTypes::DRAG_EVENT_SOURCE_COUNT);
+
   source_current_window_ = None;
   DCHECK(!g_current_drag_drop_client);
   g_current_drag_drop_client = this;
@@ -655,6 +663,7 @@ int DesktopDragDropClientAuraX11::StartDragAndDrop(
   source_state_ = SOURCE_STATE_OTHER;
   drag_operation_ = operation;
   negotiated_operation_ = ui::DragDropTypes::DRAG_NONE;
+  current_drag_event_source_ = source;
 
   const ui::OSExchangeData::Provider* provider = &data.provider();
   source_provider_ = static_cast<const ui::OSExchangeDataProviderAuraX11*>(
@@ -723,6 +732,8 @@ void DesktopDragDropClientAuraX11::Drop(aura::Window* target,
 }
 
 void DesktopDragDropClientAuraX11::DragCancel() {
+  UMA_HISTOGRAM_ENUMERATION("DragDrop.Cancel", current_drag_event_source_,
+                            ui::DragDropTypes::DRAG_EVENT_SOURCE_COUNT);
   move_loop_->EndMoveLoop();
 }
 
@@ -760,7 +771,7 @@ void DesktopDragDropClientAuraX11::OnMouseReleased() {
   if (source_state_ != SOURCE_STATE_OTHER) {
     // The user has previously released the mouse and is clicking in
     // frustration.
-    move_loop_->EndMoveLoop();
+    DragCancel();
     return;
   }
 
@@ -774,10 +785,11 @@ void DesktopDragDropClientAuraX11::OnMouseReleased() {
         // Start timer to end the move loop if the target takes too long to send
         // the XdndStatus and XdndFinished messages.
         StartEndMoveLoopTimer();
+        DragCancel();
         return;
       }
 
-      move_loop_->EndMoveLoop();
+      DragCancel();
       return;
     }
 
@@ -791,8 +803,13 @@ void DesktopDragDropClientAuraX11::OnMouseReleased() {
 
       // We have negotiated an action with the other end.
       source_state_ = SOURCE_STATE_DROPPED;
+      UMA_HISTOGRAM_ENUMERATION("DragDrop.Drop", current_drag_event_source_,
+                                ui::DragDropTypes::DRAG_EVENT_SOURCE_COUNT);
       SendXdndDrop(source_current_window_);
       return;
+    } else {
+      DragCancel();

[mfomitchev, 2015/01/13 17:01:25]

Unless there is a good reason not to, just let it fall through to
EndMoveLoop()/DragCancel() at the bottom.

[caelyn, 2015/01/13 23:48:58]

Done.

+      return;
     }
   }